Showing posts with label Azores Triple Junction. Show all posts
Showing posts with label Azores Triple Junction. Show all posts

Tuesday, 30 April 2013

Magnitude 5.9 Earthquake in the Azores.

On Tuesday 30 April, slightly after 6.25 am local time (which is GMT), the United States Geological Survey recorded a Magnitude 5.9 Earthquake at a depth of 10 km in the Azores, roughly 20 km southeast of São Miguel Island. This is a large Earthquake, and is likely to have been felt across much of the archipelago, though it was probably far enough offshore to avoid any serious damage or injuries.

The location of the 30 April 2013 Earthquake. Google Maps.

The Azores are a group of volcanic islands belonging to Portugal, strung out along the boundary between the African and European plates to the east of the Mid-Atlantic Ridge. This is currently an area of expansion, with the two plates moving apart along this part of the boundary and new seafloor being created by the upwelling of magma from the mantle and its extrusion as a new area of crustal material, the Azores Microplate. This is not a smooth process, and can lead to occasional Earthquakes.

The location of the Azores relative to the Mid-Atlantic Ridge. (Martins et al. 2008)


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Wednesday, 6 June 2012

Earthquake in the Azores.

On Tuesday 5 June 2012, slightly after 7.45 am local time (which is GMT), an Earthquake struck in the Azores, roughly 140 km southeast of Santa Cruz das Flores and 171 km west of Horta. This was recorded by the United States Geological Survey as measuring 4.9 on the Richter Scale and occurring at a depth of 10 km. There are not reports of any injuries or damage, and a quake of this size so far from land may not have been felt by anyone.

Map showing the location of the 5 June 2012 quake. USGS.

The Azores lie on the junction of the Mid-Atlantic Ridge (a divergent margin) and the boundary between the Eurasian and African Plates (a convergent margin), where they occupy their own microplate (the Azores Microplate). The islands are volcanic in nature, with volcanoes fed both by the upwelling of magma under the Mid-Atlantic Ridge, and by material from the subducting African Plate, which is melted as it sinks into the Earth, both by the heat of the planets interior and by the friction of the converging plates.

The plate margins around the Azores. GESPEA (Working Group on


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